Examination of wind storms over Central Europe with respect to circulation weather types and NAO phases
Examination of wind storms over Central Europe with respect to circulation weather types and NAO phases
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DOI：
10.1002/joc.1982
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发表时间：
2010-07-01
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影响因子：
--
通讯作者：
Ulbrich, Uwe
中科院分区：
文献类型：
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作者：
Donat, Markus G.;Leckebusch, Gregor C.;Ulbrich, Uwe
本文从大尺度大气流动和局地风速的角度研究了中欧地区风暴的发生。中欧作为目标区域，采用了两种不同的风暴识别方法：一种是基于大尺度流的特征（环流天气类型，CWT），另一种是基于极端风速的发生。所确定的事件将根据NAO阶段和它们发生的cwt进行检查。在不同的暴风中心，我们会研究风暴的气压模式、风速和气旋路径。调查是基于ERA40再分析数据。结果表明，中欧地区约80%的风暴日数与西风气流有关，中欧风暴事件主要发生在中等正态NAO阶段，而强正态NAO阶段（占总日数的6.4%）占20%以上。在NAO指数为强正的日子里，中欧约有10%的日子会发生风暴。与中欧风暴有关的气旋系统最常见的路径是从北大西洋经过不列颠群岛、北海和斯堪的纳维亚半岛南部进入波罗的海。这些系统的平均强度通常在不列颠群岛附近达到最大值。CWT识别程序（基于MSLP场的大风日）识别的风暴特征与中欧栅格点的极端风特征之间的差异很小，尽管只有70%的风暴日是一致的。虽然大多数风暴发生在西风道情况下，但其他CWTs期间风暴的具体特征也被考虑在内。版权所有(C) 2009皇家气象学会
The occurrence of wind storms in Central Europe is investigated with respect to large-scale atmospheric flow and local wind speeds in the investigation area. Two different methods of storm identification are applied for Central Europe as the target region: one based on characteristics of large-scale flow (circulation weather types, CWT) and the other on the occurrence of extreme wind speeds. The identified events are examined with respect to the NAO phases and CWTs under which they occur. Pressure patterns, wind speeds and cyclone tracks are investigated for storms assigned to different CWTs. Investigations are based on ERA40 reanalysis data.It is shown that about 80% of the storm days in Central Europe are connected with westerly flow and that Central European storm events primarily occur during a moderately positive NAO phase, while strongly positive NAO phases (6.4% of all days) account for more than 20% of the storms. A storm occurs over Central Europe during about 10% of the days with a strong positive NAO index. The most frequent pathway of cyclone systems associated with storms over Central Europe leads from the North Atlantic over the British Isles, North Sea and southern Scandinavia into the Baltic Sea. The mean intensity of the systems typically reaches its maximum near the British Isles. Differences between the characteristics for storms identified from the CWT identification procedure (gale days, based on MSLP fields) and those from extreme winds at Central European grid points are small, even though only 70% of the storm days agree. While most storms occur during westerly flow situations, specific characteristics of storms during the other CWTs are also considered. Copyright (C) 2009 Royal Meteorological Society